The present invention relates generally to an ignitor monitoring device disposed within a housing that is independent of the luminaire. More specifically, the invention provides for a device that tests for the presence of a hot re-strike ignitor pulse having a minimum threshold voltage.
High intensity discharge luminaires, hereinafter referred to as HID luminaires, are commonly installed at high locations at commercial or industrial facilities such as on the ceiling of a warehouse or plant, or on light poles in a parking lot or stadium. HID luminaires can include, but are not limited to, metal halide (MH) lamps, and high pressure sodium (HPS) lamps. Some MH luminaires and all HPS luminaires use pulses from a high voltage source such as an ignitor circuit to ignite the lamp.
In many applications, the HID luminaires can be elevated on the order of thirty feet or more above the ground or floor of a commercial or industrial facility. The elevation of the luminaires makes repairs of malfunctioning luminaires inconvenient and time consuming since service personnel must ascend to considerable heights in order to gain access to the luminaires, assess the problem and then repair or replace the defective components of the luminaire. The malfunctioning of the HID can be attributable, for example, to a defective lamp starting circuit, also referred to as an ignitor. Specifically, if the ignitor does not produce a minimum threshold voltage, the lamp does not illuminate, thereby failing to establish initiation of the arc.
A number of devices exist to facilitate the assessment of a malfunctioning luminaire. For example, U.S. Pat. No. 4,496,905, to Forte et al., discloses an ignitor testing device with indicator lights to inform the user of various possibilities for luminaire failure. The device replaces the lamp in the luminaire housing, thus measuring the voltage provided across the lamp. In addition, the ignitor testing device employs a circuit with multiple elements in order to assess the positive and negative waveforms of the open circuit voltage signal. These multiple elements require a larger surface area on the circuit board and therefore a larger housing, which makes the device less portable. Thus, a need exists for an ignitor monitoring device that employs fewer elements in order to facilitate a smaller housing.
Further, the ignitor producing the open circuit voltage disclosed in U.S. Pat. No. 4,496,905 is not a hot re-strike ignitor, but rather a standard ignitor that is only able to re-strike after 45 seconds to 1.5 minutes, that is, only after sufficient time has elapsed for the lamp portion of the luminaire to cool down. Therefore, a need exists for an ignitor monitoring device that is able to test a hot re-strike ignitor yet maintain the portability function, as mentioned above. Such a hot re-strike ignitor is disclosed for example, in U.S. Pat. No. 5,047,694 to Nuckolls et al., and U.S. Pat. No. 5,321,338 to Nuckolls et al., the contents of both being incorporated herein by reference.
U.S. Pat. No. 6,127,782, to Flory, IV et al., also discloses an ignitor monitoring device that provides an indication of sufficient open circuit voltage to operate the ignitor. In contrast with the ignitor monitoring device disclosed in U.S. Pat. No. 4,496,905, the ignitor monitoring device disclosed in U.S. Pat. No. 6,127,782 is externally mountable to the luminaire housing. Thus, rather than replacing the lamp via a removable test housing, a receptacle that is distinct from the lamp socket, is provided to enable the ignitor monitoring device to be attached to the luminaire housing. Thus, each lamp has an attached and dedicated ignitor monitoring device. Accordingly, a need exists for a portable ignitor monitoring device with various delivery systems that can be readily coupled and uncoupled to different luminaires for troubleshooting purposes.
The present invention overcomes the deficiencies of existing ignitor monitoring devices and realizes a number of advantages over these devices. An ignitor monitoring device is provided in accordance with the present invention that is portable to enable testing of different lurninaires for the presence of an ignitor pulse via a pulse voltage associated with the lamp, therein. The ignitor monitoring device of the present invention is disposed on a circuit board within a housing that has two embodiments, for example, comprising a screw-in delivery housing and a plunger delivery housing.
The ignitor monitoring device of the present invention, for example, comprises a voltage threshold circuit, a gating circuit, an indicator device, a signal conditioning circuit, and a current discharge circuit. The voltage threshold circuit is operable to determine whether the pulse voltage is a minimnum threshold voltage, thereby indicating if the ignitor is striking at a sufficiently high voltage level to operate the lamp. The gating circuit is operable to conduct current when the open circuit voltage reaches the minimum threshold voltage, thereby allowing the indicator device to illuminate and indicate a sufficient ignitor pulse for lamp operation, as well as hot re-strike capability. The current discharge circuit is also operable to discharge residual current within the ignitor monitoring device. This discharge circuit is a safety feature to dissipate the residual charge on the circuit board within the housing thereby reducing the risk of exposing the user of the ignitor monitoring device to electrocution.
The present invention also provides a method for testing one of a plurality of luminaires for the presence of an ignitor pulse via a pulse voltage associated with the luminaires. The method comprises, first, determining whether the pulse voltage is a minimum threshold voltage and secondly, conducting current through a gating circuit such as an SCR when the pulse voltage is at the minimum threshold voltage. The method also comprises illuminating an LED in response to current flow indicating the ignitor is maintaining a minimum voltage pulse.
In accordance with an aspect of the present invention, the ignitor monitoring device is disposed on a circuit board within a housing that is external to the luminaire. In addition, the housing couples and decouples via a plunger device or a screw-in device, allowing for ease of use when testing.
In accordance with another aspect of the present invention, the ignitor monitoring device monitors the ignitor pulse on every positive one-half cycle of the waveform, thus allowing use of fewer components.
In accordance with another aspect of the present invention, the ignitor monitoring device is provided for use with a hot re-strike ignitor, as opposed to a conventional HID lamp ignitor requiring a cool down period before re-striking can occur.